Arc welding has been known from convention. In arc welding, when the feed rate of the arc torch quickens, the arc runs behind in the direction of advancement of the arc torch, and a phenomenon occurs in which heat does not penetrate the workpiece. In this case, welding is carried out while the workpiece remains not sufficiently preheated, which is a cause of welding defects.
In order to resolve the above-mentioned phenomenon, for example, technology has been proposed that causes the arc A to swing forwards in the direction of advancement of an arc torch 100, using the Lorentz force F (shown by F in FIG. 28) produced by causing a magnetic field in a direction orthogonal to the joining direction (shown by B in FIG. 28) to act on the arc A extending from the leading end of the nozzle of the arc torch 100 to the workpiece W, as shown in FIGS. 27 and 28 (refer to Patent Document 1).
Patent Document 1: Japanese Unexamined Patent Application, Publication No. S61-206566